217297081 has 3 divisors (see below), whose sum is σ = 217311823. Its totient is φ = 217282340.

The previous prime is 217297061. The next prime is 217297097. The reversal of 217297081 is 180792712.

The square root of 217297081 is 14741.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 211440681 + 5856400 = 14541^2 + 2420^2 .

It is not a de Polignac number, because 217297081 - 2⁵ = 217297049 is a prime.

It is a super-2 number, since 2×217297081² = 94436042822241122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 217297081.

It is not an unprimeable number, because it can be changed into a prime (217297001) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 7371 + ... + 22111.

Almost surely, 2^217297081 is an apocalyptic number.

217297081 is the 14741-st square number.

217297081 is the 7371-st centered octagonal number.

It is an amenable number.

217297081 is a deficient number, since it is larger than the sum of its proper divisors (14742).

217297081 is an frugal number, since it uses more digits than its factorization.

217297081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29482 (or 14741 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 37.

The cubic root of 217297081 is about 601.1986049086.

The spelling of 217297081 in words is "two hundred seventeen million, two hundred ninety-seven thousand, eighty-one".